This invention relates to a reversible rotary actuator having an electric motor which is selectively operable to drive an output member in either of two directions. The output member may, for example, be a flow-controlling damper which is adapted to be turned between fully open and fully closed positions in an air duct. When the damper is stopped in either of those positions, the motor stalls and, with many prior actuators, the motor remains in the stalled condition and wastefully consumes electric power.